Pivoting rotary screen end ring mount

ABSTRACT

A tubular printing screen has spaced axial ends each of which is provided with a mounting ring. A support is provided adjacent each of these ends and carries a journal ring unit turnably mounted thereon. A pair of pivot joints are provided, each connecting one of the mounting rings with a respectively associated journal ring unit.

I United States Patent [1 1 1111 3,881,413 Mitter May 6, 1975 [54] PIVOTING ROTARY SCREEN END RING 2,711,935 6/1955 Miles 101/219 X MOUNT 2,762,295 9/1956 Varga et a]. 101/219 X 3,675,571 7/1972 venegaal 101/116 X Inventor: Mathias Mitler, Senna, e y 3,718,086 2/1973 Vertegaal 101/120 x [73] Assignee: Mitter & Co., Schloss Holte,

Germany Primary Examiner-Edgar S. Burr 22 Filed: Nov 8, 1973 Assistant ExaminerR. E. S11E81 I [21] A l N 413 991 Attorney, Agent, or Frrm-M1chae1 S. Striker [30] Foreign Application Priority Data ABSTRACT Nov. 9, 1972 Germany 2254819 A tubular printing Screen has spaced axial ends each of which is provided with a mounting ring. A support [52] US. Cl 101/127.1; 101/128.1 is provided adjacent each of these ends and carries a [51] 111- CI. B41f 15/38; B4111 l/24 journal g unit turnably mounted thereon A p of [58] Fleld of Search 101/116-122, I pivot joints are provided, each connecting one of the 101/127'1 1281 219 mounting rings with a respectively associated journal rin unit. [56] References Cited g UNITED STATES PATENTS 7 Claims, 3 Drawing Figures 1,330,793 2/1920 Friess 101/219 X PATENTED HAY 6 I975 SHEET 2 BF 2 PIVOTING ROTARY SCREEN END RING MOUNT BACKGROUND OF THE INVENTION The present invention relates generally to screen printing machines, and more particularly to the manner in which a tubular printing screen is mounted in a screen printing machine.

Screen printing machines of various types are known. These include a type wherein the printing screen is in form of a tubular construction, that is essentially a drum the opposite axial ends of which are provided with mounting rings which are fixed to the tubular printing screen. It is known to provide supports adjacent the opposite axial ends of the tubular printing screen, and to provide journal rings on these supports, each journal ring being connected with one of the mounting rings. The arrangement according to the prior art is such that each journal ring is arranged concentrically with reference to the associated mounting ring.

In many instances during the operation of a screen printing machine having a tubular printing screen, it is necessary that the thus mounted printing screen be adjusted and possibly axially tensioned. For this purpose the prior art provides, for instance, to make one of the supports adjacent one axial end of the printing screen turnable, whereas the other support is both turnable and shiftable axially and radially of the printing screen. This, of course, makes it possible to influence the positioning and axial tensioning of the printing screen-- -which latter is of very thin sheet material--as desired prior to operation of the screen printing apparatus.

However, although this is highly advantageous in terms of the results achieved, experience has shown that during the operation the printing screen undergoes changes which are not usually detected by an operator and which may result from the influence exerted upon the printing screen by the interiorly located squeegee, the movement of the ink in the interior with reference to the printing screen, and other factors. In particular, this may lead to the development of stresses in the printing screen which in turn can result in inaccurate adjustment of the printing screen and to an improper printing. Also, it can lead to the development of torsional forces which can lead to damage and possibly destruction of the tubular printing screen.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the disadvantages of the prior art.

More particulary, it is an object of the present invention to provide, in a screen printing machine having a tubular printing screen, an arrangement wherein these disadvantages of the prior art are overcome.

An additional object of the invention is to provide such an arrangement wherein the tubular printing screen is so mounted that to all intents and purposes it will adjust and accommodate itself to changes which occur in operation of the apparatus.

In keeping with the above objects, and with others which will become apparent hereafter, one feature of the invention resides, in a screen printing machine, in a combination which comprises a tubular printing screen having spaced axial ends. A support is provided adjacent each of these ends, and a pair of mounting rings is provided, each being fixed to one of the axial ends. A pair of journal ring units is also provided, each of these being turnably mounted on one of the supports. A pair of pivot joints is provided, of which each connects one of the mounting rings with the respectively associated journal ring unit.

The axes about which the pivot joints at the opposite axial ends of the printing screen can pivot, should advantageously extend normal to one another so that in effect together they constitute a single universal joint, i.e., a multidirectiona] pivot mount, which assures that the printing screen will always be free of tensions because automatic compensation of the tensions will take place. During the operation, that is during the rotation of the printing screen, the latter can continuously adjust itself to differing conditions, so that no danger of damage or destruction of the printing screen exists, and all those disadvantages are eliminated which result from the development of stresses in the printing screen.

It is advantageous if the supports are adjustable in all possible direction, in a manner already well known from the art, because this makes possible an initial exact setting of the printing screen by means of displacement of the supports, so that the arrangement according to the present invention need provide for automatic compensation of only those difficulties which arise when deviations occur from the initial setting during the operation of the machine.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view, showing one end of a printing screen with a pivot joint thereon;

FIG. 2 shows the arrangement of FIG. 1, but with the components of the pivot joint not yet assembled; and

FIG. 3 is a somewhat diagrammatic view, illustrating the tubular printing screen, the supports at the opposite ends of the same, and the pivot joints connecting the opposite axial ends of the printing screen to the supports.

DESCRIPTION OF THE PREFERRED I EMBODIMENTS Referring now to the drawing, wherein FIG. 3 provides an overview of a tubular printing screen which is mounted in accordance with the present invention, whereas FIGS. 1 and 2 show details of a pivot joint provided at one axial end of the tubular printing screen, it will be appreciated that those details of a screen printing machine which are not essential for an understanding of the present invention, have been omitted from the drawing.

FIG. 3 shows that the tubular printing screen 1 is mounted in supports S which are located adjacent the opposite axial ends of the printing screen. The supports S have been omitted in the illustration of FIGS. 1 and 2, as has been one end of the tubular printing screen since the illustration of the pivot joint adjacent the illustrated end in FIGS. 1 and 2 is sufficient for an understanding of the invention, the opposite pivot joint being identical with the one illustrated, with the only difference that the pivot axis about which the joint can pivot extends normal to the pivot axis of the joint which is illustrated in FIGS. 1 and 2, thus the joints together form a multidirectional pivot mount for the screen.

The supports S carry the journal ring units 2 which are so mounted that they permit rotation and also an axial tensioning of the tubular printing screen. For this purpose, the supports S can be appropriately adjusted in accordance with the prior art, that is they can be moved axially and radially of the printing screen and can be arrested in desired positions by means and devices known per se.

The main adjustment of the tubular printing screen 1 is carried out by means of this displacement of the supports S.

Each of the opposite axial ends of the printing screen 1 is provided with a mounting ring 3 which is fixedly connected with the printing screen. The use of such mounting rings is already known per se. In accordance with the present invention, however, the mounting rings 3 illustrated in particular in FIGS. 1 and 2 are provided at two diametrically opposite locations with lugs or projections 30 which are formed with registering openings.

Each of the units 2 is in turn provided with a retaining ring 4 which is rotatably journalled in the respective unit 2 and is itself provided at two diametrically opposite locations with two further lugs or projections 4 which also have registering openings.

According to the present invention, the cooperating rings 3 and 4 are so positioned that each of the lugs 30 is located in overlapping relationship with one of the lugs 40 so that the openings in them register with one another. This is the position which is shown in FIG. 1 and to which the lugs are moved during assembly. FIG. 2 shows the rings 3 and 4 in a position just prior to assembly, and it will be appreciated that either the ring 3 or the ring 4 or both of them will have to be turned until their lugs 30 and 40 overlap in the position shown in FIG. 1. Screws, bolts or other pivots 5 are then inserted through the registering openings of the lugs 30, 40 and the two screws, etc., 5 (only one shown) define with one another a pivot axis for the respective pivot joint.

This pivot axis extends at one axial end of the printing screen 2 in one orientation, for instance horizontally, and at the pivot joint at the opposite axial end the pivot axis of that pivot joint may extend in direction normal to the pivot axis of the first-mentioned joint, so that if the pivot axis of the first-mentioned joint has a horizontal orientation the one at the opposite axial end may have a vertical orientation. The two joints together thus form, in effect, a univeral joint.

The arrangement of the lugs 30 and 40 in the manner illustrated makes possible not only a simple connection between the rings 3 and 4, but also a similarly simple disengagement. It is merely necessary to remove the elements 5 and to turn the tubular printing screen 1 in the direction of the arrow A shown in FIG. 2, which, of course, causes a similar turning of the ring 3 which is fixedly connected with the screen 1, so that the lugs 30 and 40 are no longer in overlapping relationship. Now, the printing screen 1 with the rings 3 provided at its opposite axial ends can readily be lifted out from between the rings 4 at its opposite axial ends, in the direction of the arrow B shown in FIG. 2. Evidently, if the screen 1 is turned to a position in which the lugs 30 and 40 assume a different relationship from that shown in FIG. 2 relative to one another, the screen 1 will be lifted out from between the rings 4 in a direction other than that indicated by the arrow B.

The central concept of the present invention is to provide the pivot joints at the opposite axial ends of the tubular printing screen 1, in such a manner that together they form, in effect, a universal joint. This can be achieved in a particularly simple and effective manner with the arrangement illustrated in the drawing. It should be understood, however, that other ways exist and are conceivable for obtaining the same effect, and they are quite evidently intended to be included within the concept of the present invention.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of construction differing from the type described above.

While the invention has been illustrated and described as embodied in a screen printing machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a screen printing machine, a combination comprising a tubular printing screen having spaced axial ends; a support adjacent each of said ends; a pair of mounting rings each fixed to one of said axial ends; a pair of journal ring units each fixedly mounted on one of said supports; and two pivot joints each connecting one of said mounting rings with a respectively associated journal ring unit, said pivot joints together forming a multi-directional pivot mount which allows said tubular printing screen to yield in response to fluctuations in the spacing which exists between said tubular printing screen and material which is being printed upon.

2. A combination as defined in claim 1, wherein each of said journal ring units includes a retaining ring; and wherein said pivot joints include a pair of diametrically opposite first lug portions projecting axially from the respective mounting ring toward the associated ring unit, a pair of diametrically opposite second lug portions projecting axially from the respective ring unit toward the associated mounting ring and each overlapping one of said first lug portions, and pivot means connecting each first lug portion with the respectively overlapping second lug portion.

3. A combination as defined in claim 2, wherein said pivot means comprises bolts, and wherein the bolts connecting the first lug portions of each mounting ring with the second lug portions of an associated retaining ring are coaxial with one another.

4. A combination as defined in claim 1, wherein each of said pivot joints permits relative pivoting of said mounting rings with reference to the respectively associated ring unit about a pivot axis; and wherein the 6 mounting ring has an axial end face facing but axially spaced from a similar axial end face of the associated retaining ring.

7. A combination as defined in claim 5, wherein the outer diameter of each retaining ring is smaller than the inner diameter of the associated mounting ring. 

1. In a screen printing machine, a combination comprising a tubular printing screen having spaced axial ends; a support adjacent each of said ends; a pair of mounting rings each fixed to one of said axial ends; a pair of journal ring units each fixedly mounted on one of said supports; and two pivot joints each connecting one of said mounting rings with a respectively associated journal ring unit, said pivot joints together forming a multi-directional pivot mount which allows said tubular printing screen to yield in response to fluctuations in the spacing which exists between said tubular printing screen and material which is being printed upon.
 2. A combination as defined in claim 1, wherein each of said journal ring units includes a retaining ring; and wherein said pivot joints include a pair of diametrically opposite first lug portions projecting axially from the respective mounting ring toward the associated ring unit, a pair of diametrically opposite second lug portions projecting axially from the respective ring unit toward the associated mounting ring and each overlapping one of said first lug portions, and pivot means connecting each first lug portion with the respectively overlapping second lug portion.
 3. A combination as defined in claim 2, wherein said pivot means comprises bolts, and wherein the bolts connecting the first lug portions of each mounting ring with the second lug portions of an associated retaining ring are coaxial with one another.
 4. A combination as defined in claim 1, wherein each of said pivot joints permits relative pivoting of said mounting rings with reference to the respectively associated ring unit about a pivot axis; and wherein the pivot axis of the pivot joint at one of said axial ends extends normal to the pivot axis of the pivot joint at the opposite one of said axial ends.
 5. A combination as defined in claim 2, wherein each of said mounting rings and the respectively associated retaining ring overlap one another only with their first and second lugs, respectively.
 6. A combination as defined in claim 5, wherein each mounting ring has an axial end face facing but axially spaced from a similar axial end face of the associated retaining ring.
 7. A combination as defined in claim 5, wherein the outer diameter of each retaining ring is smaller than the inner diameter of the associated mounting ring. 